1) Field of the Invention
The present invention relates to a distance measuring apparatus which emits pulse light toward a target and computes the distance to the target by measuring a period of time from the emission of pulse light until the detection of reflected pulse light.
1) Related Background Art
Conventionally known as an apparatus which emits a laser pulse toward a target, receives the light reflected by the target, and computes the distance to the target is, for example, that disclosed in Japanese Patent Application Laid-Open No. 53-1553.
This conventional distance measuring apparatus comprises a single measuring system which emits a laser pulse into a measurement optical path between the apparatus and a target and receives the reflected pulse light propagated through the measurement optical path; and computes the distance to the target according to the difference in time between the timing at which the laser pulse is emitted by the single measuring system and the timing at which the reflected pulse light is received by the same system.
In particular, in order to eliminate reflected signals from a reflective object located farther than the target, the conventional distance measuring apparatus adjusts the beam expansion of the laser light emitted therefrom such that the laser light does not reach anywhere other than the target. Also, the conventional distance measuring apparatus sequentially records temporal information of the reflected signal being received each time a laser pulse is emitted toward the target, and computes information about the distance to the target on the basis of the finally recorded temporal information of the reflected signal.